1. Field of the Invention
The present invention relates to a water-cooling type cooler and, more particularly, to a water-cooling type cooler having a simple cooling water flow path to maximize a cooling performance of a water-cooling type inverter used for an electric vehicle or the like as well as to enhance a cooling effect.
2. Description of the Related Art
In general, an internal combustion engine such as a petroleum engine commonly used as a vehicle engine uses thermal energy generated by burning fuel within a cylinder, as power. Exhaust discharged after combustion from the internal combustion engine contains harmful components such as nitrogen oxide due to the combustion and carbon monoxide and hydrocarbon due to imperfect combustion, contaminating air. Thus, over the environmental pollution problem and the exhaustion of fossil fuel, research on vehicle engine using alternative energy such as solar heat or electricity is actively ongoing in many countries.
Among vehicle engines using alternative energy, an electric vehicle engine, which drives vehicle by using electrical energy has the highest feasibility of commercialization. The electric vehicle engine has a structure in which a motor is rotated by electricity supplied from a storage battery, instead of gasoline of a petroleum engine, generated rotary power of the motor is decelerated by a decelerator, and the decelerated rotary power is transferred to left and right driving wheels through a differential gear, thus allowing for running of a vehicle.
The electric vehicle is based on a principle that a driving motor constituting a driving system is driven by electricity supplied from the storage battery corresponding to an energy source to transfer power to the wheels. The driving system including the driving motor and an inverter that controls the driving motor generates high temperature heat during the driving process due to its structural characteristics and operational characteristics, so a cooling system is operated in order to remove the high temperature heat. Namely, the system for cooling the driving system is circulated in the order of radiator→cooling pump→inverter→driving motor→and radiator.
The driving motor constituting the driving system is designed to have such durability as to tolerate heat to a degree, but the inverter including numerous electronic chips is very sensitive. Thus, when the inverter is not properly cooled, heat makes a bad influence to the operation or controlling of the inverter and melts the soldering that bonds elements to cause a connection deficiency of circuits. Also, a circuit board installed within a main body of the inverter generally includes a power module, a control board, a power board, and a driving board. In particular, heat is mostly generated from the power module including a plurality of power switching elements.
Thus, the related art water-cooling type cooler is known to be configured such that a cooling water flow path is formed on a bottom surface of a cooler constituting the main body of the inverter and having a power module coupled on its upper surface and cooling water is allowed to flow to the cooling water flow path to cool the power module. The cooling water flow path of the water-cooling type cooler is formed to have a zigzag shape to allow cooling water to extensively be brought into contact with the cooling water flow path for a longer period of time. The shape of the cooling water flow path may differ depending on the position of the power module installed within the inverter, or may differ depending on the number or positions of power switching elements constituting the power module. Cooling pins are formed at the cooling water flow path in order to increase the contact area with cooling water. The cooling pins are configured such that their pitch is narrower at an area from which a larger amount of heat is generated and their pitch is wider at an area from which a smaller amount of heat is generated, according to the amount of generated heat of the power module.
FIG. 1 is a plan view of a cooling water flow path of the related art water-cooling type cooler.
As illustrated, the cooling water flow path of the related art water-cooling type cooler 1 includes a first flow path part 11 forming a single linear flow path, a second flow path part 12 connected to the first flow path part 11 and forming a single curved flow path, and a third flow path part 13 connected to the second flow path part 12, forming a linear flow path, and forming a plurality of channels by means of a plurality of cooling pins 15.
A single first flow path part 11 is formed, while a plurality of second and third flow path parts 12 and 13 are alternately formed. The first flow path part 11 is connected to an entrance 2 of the water-cooling type cooler 1, and the third flow path part 13 is connected to an exit 3 of the water-cooling type cooler 1.
In the related art water-cooling type cooler 1 as described above, cooling water is introduced through the entrance 2, pass through the first and second flow path parts 11 and 12, and then enters the third flow path part 13. In this case, because the third flow path 13 is divided into a plurality of flow paths by the cooling pins 15, the cooling water, which has entered the third flow path part 13, is distributed to the plurality of flow paths in passing through the third flow path part 13. In this process, the cooling water is brought into contact with the cooling pins 15, quickly cooling components that generated much heat like the power module. After the cooling water alternately passes through the second and third flow path parts 12 and 13 which are continued, and then discharged through the exit 3. This sequential processes are repeatedly performed.
However, the related art water-cooling type cooler 1 has the following problem. That is, because the flow path of cooling water is bent at the curved portion, namely, at the second flow path 12, the cooling water is concentrated to an outer side due to centrifugal force, resulting in an uneven distribution of cooling water. In addition, because a flow rate of an outer side is relatively faster, generating vortex to degrade the flow of cooling water. In order to overcome this problem, a plurality of cooling pin may be formed in the second flow path part 12, but in this case, a fabrication cost and weight of the water-cooling type cooler 1 increase to lead to an increase in the weight of an electric vehicle employing the inverter having the water-cooling type cooler 1, causing a problem in that the performance of the vehicle deteriorates.